Not true. I dropped my XP installation from my 680i into an E520 while I was buying new hardware, and it didn't ask for validation at all. It's kind of random as to when it asks.

Interesting... The thing is that I've swapped GPUs idk how many times on this system, and it never did anything about it, but the second the PSU blows, this starts. I hope it's a coincidence, but I do not think so right now.

Windows tends to be like that when hardware changes. I just don't know the frequency. I changed 3 systems and still didn't asked for me, some asked within a couple of changes, and yours was at the first one. It's unclear as to when it'll ask.